The present invention is directed to a control system for moving a reel on a harvesting platform fore and aft.
Agricultural combines are provided with harvesting platforms. These harvesting platforms typically comprise a transversely extending frame having a transversely extending auger and reel. The frame is provided with a front edge having a cutter bar for cutting a standing crop. The central rear portion of the frame is provided with a central opening through which harvested crop is directed to the feeder house of the combine.
The fore/aft position of the reel relative to the frame is controlled by an operator located in the operator""s station of the combine. As the combine moves through a field, crop conditions change, requiring the operator to change the fore/aft position of the reel relative to the frame to maintain optimal harvesting performance. For example, if the operator encounters downed crop (standing crop that has blown over) he would want to move the reel forwardly and downwardly to better engage the downed crop. Similarly for crop standing upright the operator would want the reel moved rearwardly from the forward most position.
Combines have been provided with fore/aft control systems for harvesting reels. In these systems the harvesting platform is provided with a fore/aft reel position sensor that generates a fore/aft position signal that is directed to a controller. The controller in turn controls the extension and retraction of hydraulic cylinders that move the reel fore and aft by signaling an electrohydraulic circuit control hydraulic valves. The controller is typically provided with additional inputs for manually controlling the fore/aft position of the reel and for placing the reel in a preselected fore/aft position relative to the frame.
The fore/aft position sensors used on these systems have used a potentiometer to generate the fore/aft position signal. The signaling potentiometer is coupled to the reel and/or saddles by linkages that may need adjustment.
It is an object of the present invention to provide a simple and robust fore/aft position sensor for a harvesting reel.
The harvesting reel is rotatably mounted on saddles that are slidably positioned on fore/aft extending arms. The fore/aft position of the saddles is controlled by hydraulic cylinders. The fore/aft position sensor is located between one of the fore/aft extending arms and the respective saddle. The fore/aft extending arm is provided with a slot that extends along the arm at a vertical angle. A sensing finger engages the slot and is coupled to a signal generator by a sensing arm. The signal generator comprising a potentiometer. As the fore/aft position of the reel changes, the vertical position of the sensing finger changes creating an electrical output from the potentiometer. The resulting potentiometer voltage represents a fore/aft position signal that is directed to a controller.